Automatic reclosing circuit breakers



Oct. 30, 1956 J. M. WALLACE ET AL 2,759,056

AUTOMATIC RECLOSING CIRCUIT BREAKERS Filed July 5, 1951 Fig.|.

WITNESSES: INVENTORS z'::'2:w wY%'L%izS. vQ Um B 72/ I ATTORNEY UnitedStates Patent Ofitice AUTOMATIC RECLOSING CIRCUIT BREAKERS James M.Wallace, Pittsburgh, and Andrew W. Edwards,

East McKeesport, Pa., assignors to Westinghouse Electric Corporation,East Pittsburgh, Pa., a corporation of Pennsylvania Application July 5,1951, Serial No. 235,282

Claims. (Cl. 200-89) This invention relates generally to automaticreclosing circuit breakers, and particularly to such breakers as haveclosely successive circuit-interrupting operations with different timecharacteristics.

In connection with automatic reclosing circuit breakers, it is customaryto provide for one or more substantially instantaneous openings followedby delayed openings having inverse time-current characteristics. Suchdelayed characteristics have heretofore been provided by utilizing adashpot structure wherein the movable core of a solenoid coil moves inan oil-filled chamber which is vented into the interior of the breakercontainer, and varying the eifective size of the vent.

One object of this invention is to provide in an automatic reclosingcircuit breaker for using a sealed dashpot structure for delayingoperation of the breaker.

Another object of the invention is to provide in an automatic reclosingcircuit breaker for using a normally ineffective sealed dashpottime-delay structure, and for utilizing leakage magnetic flux to renderthe time-delay structure effective during opening of the breaker.

Yet another object of our invention is to provide in an automaticreclosing circuit breaker for utilizing a normally ineifective sealeddashpot time-delay structure, and utilizing magnetic means for renderingthe time-delay structure effective only after a predetermined number ofclosely successive substantially instantaneous operations.

It is also an important object of our invention to provide in anautomatic reclosing circuit breaker for utilizing an operation counterfor positioning a magnetic shunt to retard movement of a dashpottime-delay mechanism after a predetermined number of substantiallyinstantaneous openings.

These and other objects of this invention will become more apparent uponconsideration of the following detailed description of a preferredembodiment thereof, when taken in connection with the attached drawing,in which:

Figure 1 illustrates a substantially central vertical sectional view ofa circuit breaker embodying this invention, and

Fig. 2 is a sectional view taken along the line II-II of Fig. l.

The invention is illustrated on the drawing as being embodied in oneform of automatic reclosing circuit breaker, with the particular breakerherein illustrated being more particularly described and claimed in thecopending application of J. M. Wallace et al., Serial No. 8044, filedFebruary 13, 1948, on Circuit Interrupters, which is assigned to thesame assignee as this invention. This circuit breaker is mounted in ametal tank 2 having a closed bottom wall and an open top and adapted tobe filled with a liquid up to the level L, preferably anarcextinguishing liquid such as oil or the like. Preferably, the tank islined at least over the bottom wall and up to a point adjacent the opentop of the container with a liner 3 of insulating material such asfiber, or the like.

Patented Oct. 39, 156

a The upper end of tank 2 is provided with an outwardly extending flange4 on which the flange 8 of a cover casting 6 is adapted to be seated,preferably, with a gasket 10 interposed therebetween. Flange 8 of covercasting 6 may be provided with an integral lip 12, and the cover may besecured to the tank in any desired manner, such for example, as by bolts(not shown) extending through openings in cover flange 8 and secured tosuitably formed brackets on the tank.

The breaker contacts, arc-extinguishing structure, and thecontact-actuating mechanism are all adapted to be supported in tank 2from cover casting 6 by means of a plurality of integral supporting lugs16 (only one of which is shown) depending from the top wall of the covercasting and adapted to engage spacers or sleeves 18 of insulatingmaterial suitably secured to supporting lugs 16 and to an uppersupporting plate 29. A lower supporting plate 22 may be supported fromplate 20, so that a solenoid coil 24 may be mounted between supportingplates 20 and 22, with the central opening in the coil aligned withopenings provided in plates 20 and 22. Supporting plates 20 and 22,together with bolts (not shown) securing them together, are of amagnetic material, such as iron or the like, to complete a magneticcircuit of low reluctance outside of solenoid coil 24, which terminatesat opposite ends of the central opening through the coil in which theworking air gap of the coil is located. Upper plate 20 may be providedwith a peripheral groove 23 for providing an effective magnetic air gap25 for a purpose Which will be explained hereinafter. The groove 23 maybe filled by an insert of a non-magnetic material such as brass or thelike.

Spaced stationary contacts 26 of the breaker are supported within aninsulating tube 28 at the lower end thereof, and on opposite sides ofthe tube, respectively. Tube 28 which may be of any desired insulatingmaterial, such as fiber or the like, is supported at its upper end fromplate 22 by supporting brackets 30 which are welded or otherwise securedto plate 22, and have screws for securing tube 23 thereto, with theupper end of tube 28 being closely adjacent to, but spaced from plate22. Stationary contacts 26 are each mounted on its own supportingbracket 32, with each bracket having a U-shaped portion for receivingthe lower edge of the tube 28 and being secured thereto as by a bolt 34.Tube 28 has opposed vent openings 35 in opposite sides, located directlyabove stationary contacts 26, respectively.

A movable bridging contact 36 for engaging the contacts 26 is mounted onan insulating contact-actuating rod 44 by a pivot 33. The upper end ofcontact-actuating rod 44 has connecting links 46 of insulating materialpivoted thereon as by a pivot pin 48, with the upper ends of theseconnecting links mounted on a common pivot pin 50 for a pair of togglelevers 52 and 54. Toggle levers 52 and 54 are both formed of sheetmaterial, with lever 54 being bent to substantially channel form withoutwardly extending flanges 56 adapted to be received at the free endsthereof in recesses 58 provided in the spaced downwardly dependingfingers of an angled supporting bracket 69 which, in turn, is secured asby a screw 64 to a lug 62 integral with the cover casting. A coiltension spring 63 has one end hooked into an opening provided in togglelever 52, and has the opposite end thereof hooked over an integralspring support on the cover casting. Toggle lever 52 has an integralhook portion 55 passing through an opening in lever 54 to limitseparation of the levers.

It will be observed that in the closed circuit position of the breakerillustrated on the drawing, the line of action of toggle spring 68 isbelow the pivot supporting recesses 58 for toggle lever 54, and,accordingly, the

toggle spring 63 acts to bias" bridging contact 36 into engagement withstationary contacts 26 of the breaker, under a predetermined pressure.However, as soon as contact-operating rod 44 moves upwardly to separatethe bridging contact from the fixed contacts of the breaker, togglelever will pivot about recesses 58, and the line of action of togglespring 68 will thus be caused to approach that pivot point, so that inresponse to avery small contact separation the line of action of togglespring 63 will pass through pivot recesses 56, which is the oncenterposition of the resilient toggle arrangement comprising toggle levers 52and 54 and toggle spring 68. As a practical matter, the opening movementof the contacts necessary to move toggle levers 52 and 54' to theoncenter position mentioned above may be made very small, in one actualdevice being on the order of one-quarter of an inch. When toggle levers52 and 5d reach their on-center position referred to above, furtherrelative movement of the two toggle levers in the same direction isprevented because the upper edge of toggle lever 52 engages the base ofthe central channel formation of toggle lever 54. Moreover, since thepoint at which toggle spring 68 is hooked into lever 52 thensubstantially coincides with recesses53 in which toggle lever 54 pivotsduring contact-opening movement, it will be apparent that the remainderand major part of contact-opening movement will occur substantiallyuninfluenced' by toggle spring 68.

Substantially the reverse of the above operation occurs whencontact-operating rod 44 moves downwardly to close the circuit from thefull-open contact position; because during the first and major part ofcontact-closing movement, levers 52 and 54 will be in engagement, sothat such movement will be uninfluenced by toggle spring 68. However, assoon as pivot 59 passes below a line drawn from the remote end of togglespring 68 through pivot recesses 58 for link 54, toggle spring 68 willthen be effective to move the toggle levers toward the position shown inFig. 1, and the force exerted by toggle spring 653 thus tending to closethe contacts, will continue to increase as toggle levers 52 and 5 movefurther away from their on-center positions.

Solenoid coil 24 previously mentioned is adapted to be energized undercertain conditions for automatically opening the circuit breakercontacts. The central opening through coil 2d preferably is providedwith a cylindrical sleeve 74 in which a solenoid core 76 is adapted tobe slidably mounted. Instead of mounting the solenoid core directly inthe sleeve 74, it may be slidably disposed within a cylindrical casing75 which comprises an inner cylinder 77 which slidably receives the rod44, and an outer cylinder 73 which is slidably disposed in the sleeve74. Caps 79 and cover and connect the cylindrical casings 7S and 77 ateach end to seal the core 76 therein. The core 76 is disposed to fitrelatively snugly between the two casings. In order to provide a dashpottime-delay action for movement of the core 76 in the casing '75, asuitable fluid such as oil or one of the silicones, may be sealedtherein. A spring 81 normally biases the core 76 to the bottom of thecasing. An orifice 82 may be provided through the core for passage ofthe fluid, thus permitting rapid reset of the core to theposition'shown, and a washer 83 may be disposed in connection therewithto provide a one-way valve for preventing passage of the fluid throughthe orifice during upward movement of the core in the casing. A collar65 may be secured to the actuating rod 44 for the casing to reactagainst in opening the breaker under the influence of the core 76.

In order to sometimes permit the core 76 to push the casing 75 ahead ofit and effect instantaneous opening of the breaker, and to sometimesrequire the core to work slowly against the dashpot action of the fluid'in the casing 75, means such as the magnetic shunting lever 86 may beprovided for holding the casing stationary while the core 76 slowlyforces its way upwardly therein, until the gap between it and the uppersupporting plate 26 is reduced sufliciently that the force exerted by itis suflicient to overcome the magnetic attraction for the shunting lever86.

With a view to rendering the shunting lever 86 effective only after apredetermined number of substantially instantaneous openings, a countingmechanism may be provided, comprising a cylinder 86 mounted on the plate2i)" and having a' movable piston 89 disposed therein with an extension90' at the upper end of a reduced section 91 having a plurality ofspaced flanges 92. The lower end of the cylinder 38 is closed except fora vent 93 and ball check 94 which permits rapid movement upwardly, butonly relatively slow downward movement of piston 89. A lower 95 having apawl 96 t ereon for engaging the different flanges 92, successively, onclosely successive operations, is disposed to be actuated by the collar"85, forstepp'in'g the piston 8) upwardly each time the breaker opens.

The shunting lever 86 has a slot 87 for receiving the rod 44, and may bepivotally supported on the plate 20 by a pivot 97 and non-magnetichinges 98'. Springs 99' normally bias the shunting lever 86 upwardly ina counterclockwise direction to the position shown in Fig; 1'. Thepiston 89 has a cam surface 1% thereon for actuating acam lever 101 in aclockwise" direction after a predetermined number of closely successiveopenings, which lever is separately pivotally mounted on pivot 97 and isspring connected to the shunting lever 86 by springs 102 so as to beresiliently connected thereto for overcoming the bias of springs 99 andactuating the lever 86 in' a clockwise direction when cam lever M1 ismoved clockwise by piston 89 moving upward, to bridge groove 23 whenceit will be held against a spacer 103 of nonmagnetic material during anopening operation, by magnetic leakage flux, for preventing movement ofthe casing 75 and providing for dashpot action of core 76 to delaysubsequent opening of the breaker.

The circuit through the circuit breaker thus far described maynow betraced from the point where it' enters tank 2' through one of a pair ofterminal bushings 106 (only one being shown), with each bushing beingsecured to cover casting 6 and each being provided with a conductorelement which extends through the bushing, and proceeds by conductor 107directly to one fixed contact 26 of the breaker. When the contacts arein engagement, the circuit then proceeds through bridging contact 36 tothe other fixed contact 26, and then by way of a conductor 108 to oneterminal of solenoid coil 24. The other terminal of coil 24 is adaptedto be connected by a conductor 109 to the conducting means in the otherterminal bushing. It will be apparent that solenoidcoil 24 is connectedin series in the circuit through the circuit breaker so as to beenergized at all times an amount dependent upon the value of the loadcurrent flowing in the circuit.

For any given rating of circuit breaker, solenoid coil 24 is designed tobecome sufliciently energized when the load current in the circuitexceeds its rating as to attract core 76 and move it upwardly withinsleeve 74. Assuming the magnetic shunt is positioned as shown, core 76will 'move rapidly upwardly, pushing the casing 75 bodily ahead, becauseof the necessity for first displacing the liquid in casing 75 above thecore through the relatively small clearance between the core and sleeves77 and 78, before the core can move in or relative to the casing.Accordingly, the core 76 and casing 75 move together as a unit, andmovement of the core will not be slowed up by the aforesaid dashpot'action, Therefore, a substantially instantaneous opening character isticis obtained, when the casing 75 strikes the shunting lever 86, moves itin a counterclockwise direction, and hence causes lever 36 to actuatecollar 85 upwardly, at which time contact-actuating rod 44 will start tomove upwardly. As soon as actuating rod 44 moves upwardly, the forceexerted by toggle spring 68 begins to decrease and in a very shortdistance has substantially no value at all, so that the remaining majorpart of the circuit-opening movement of bridging contact 36 occursextremely rapidly due to the increasing pull on the core 76 as the airgap with plate is reduced. In any case, it is apparent that togglelevers 52 and 54 will be moved to their on-center position in the mannerpreviously described, and bridging contact 36 will be moved to itsfull-open circuit position.

When the breaker contacts have attained-their fullopen circuit position,the parts associated therewith are initially biased to return bygravity. Accordingly, the return movement will be relatively slow untilpivot point moves below the line of action of toggle spring 68 whentoggle levers 52 and 54 are in engagement, whereuponbridging contact 36will be rapidly moved to eifect a snap-action closing of the breakercontacts by toggle spring 68.

In order to provide for maintaining the breaker contacts separated andto also provide for manual operation, spring means are provided forholding the breaker contacts open in response to the occurrence of apredetermined number of closely succeeding circuit-interruptingoperations, which means can be manually actuated. This means comprises atoggle lever 110 having a slot 105 at one end thereof for receiving apin 111 mounted between spaced supporting arms 112 integral with covercasting 6. The other end of toggle lever 110 is pivoted, as by a pivotpin 113, to the adjacent end of a second toggle lever 114, and this, inturn, is mounted on a pivot pin 116 intermediate its ends on covercasting 6. A slot 120 is provided through the cover casting 6 forreceiving the other end of toggle lever 114 which acts as a manualoperating handle at the exterior of the circuit breaker casing, beingprovided with a hook eye 122 in its outer end. A coil compression spring124 is mounted on toggle lever 110 and reacts between washers mounted onthe toggle lever, one of which engages supporting pin 111, and the otherof which engages a shoulder located adjacent pivot 113. Normally, togglelevers 110 and 114 are held with pivot 113 below the center-lineconnecting pins 111 and 116, with the outer end of lever 114 positionedin and beneath an integral hood 126 on cover casting 6, in engagementwith an adjustable stop screw 12S mounted in the hood. An extension 129is provided on toggle lever 110 for effecting automatic operation of thebreaker.

In the position of toggle levers 116 and 114 illustrated, they have noeffect on operation of the circuit breaker as previously described,being normally inactive in this respect. However, the common pivot pin113 of toggle levers 110 and 114 is extended at one side toward togglelevers 52 and 54, and in the normal position of the parts extendsbeneath the adjacent flange 56 of togglelever 54. Accordingly, if it isdesired to manually open the circuit breaker contacts, a hook stick orsimilar operating member may be inserted in hook eye 122 of toggle lever114 and pulled downwardly to rotate the toggle lever in acounterclockwise direction about its supporting pivot 116 to move togglelevers 110 and 114 overcenter in an upward direction, and in doing this,the common pivot pin 113 engages the adjacent flange 56 of toggle lever54 and moves it upwardly in a counterclockwise direction, thus carryingcontact-actuating rod 44 with it to separate bridging contact 36 fromstationary contacts 26. The contacts will be held open by spring 124which maintains toggle levers 110 and 114 in their upper overcenterposition. With the breaker contacts maintained at their open circuitposition following the manual circuit-opening operation described above,it will be apparent that the outer end of toggle lever 114 projectsbelow hood 126 of cover casting 6 so as to provide .a readily visibleindication that the breaker contacts 6 v are maintained at an opencircuit position. It will further be apparent that the breaker contactsmay then be closed only by manual operation of toggle lever 114 in theopposite direction, that is, by exerting an upward force on the outerend of the toggle lever to rotate it in a clockwise direction to move itand toggle lever 110 back overcenter to the position illustrated on thedrawing. This manual operation of toggle lever 114 does not directlyclose the breaker contacts, but merely permits closure of the contactsin the manner previously described, that is, initial closing movement ofthe contacts being due to the bias of gravity, until bridging contact 36is closely adjacent stationary contacts 26, when toggle spring 68 ismoved below its on-center position and suddenly becomes eifective tofinally move the contacts into engagement rapidly.

With the parts of the circuit breaker at their normal positionsillustrated in Fig. 1, it will be apparent that when upon apredetermined overload the circuit breaker operates to open the circuit,the upper end of casing being unrestrained, solenoid core 76 and casing75 will be moved upwardly together very rapidly, since shunting lever 86is not in a position to resist movement of the casing, and consequentlythe initial circuit-opening operation of the breaker will occursubstantially instantaneously as hereinbefore described. During such aninitial fast circuit-opening operation, it will be apparent that contactrod 44 and the parts which move with this rod will be moving at arelatively high speed.

As solenoid core 76 and casing 75 move upwardly on such a firstcircuit-opening operation, collar will be carried upwardly, and willthus carry the free end of pawl lever upwardly with it to move pawlmember 96 into engagement with the upper one of flanges 92 onintegrating piston 89, and carry the piston upwardly a predetermineddistance throughout opening movement of casing 75. Integrating piston 89is not, however, carried upwardly a distance suflicient to have camsurface 16%) engage lever 101, so that the magnetic shunting lever 86remains in the position shown.

When the breaker recloses following such a first fastcircuit-interrupting operation, such reclosure will also occur extremelyrapidly, because there is no dashpot action due to the fact that thecasing 75 moves freely in the sleeve 74, and the core 76 does not moverelative to the casing 75 during such opening. Accordingly, the firstopening and reclosing of the circuit breaker contacts will both occursubstantially instantaneously with but little time delay interposed, dueto the slight drag of casing 75 in displacing the oil through which itmoves. During reclosing of the breaker the first time, integratingpiston 89 is left at the position to which it was advanced, since pawlmember 96 is free to disengage the circular flanges 92, and if thebreaker remains closed, integrator piston 89 Will slowly reset to theposition shown in Fig. 1, this resetting movement being relatively slowdue to the necessity of displacing liquid drawn into the lower end ofcylinder 88 by advancement of piston 89 during the opening operation,past the relatively small clearance between cylinder 88 and piston 89.This means, of course, that if an overload appears on the circuit at alater time, the breaker contacts will then be substantiallyinstantaneously opened and closed in the manner described above.

If the breaker immediately reopens after a first opening and reclosingoperation, pawl member 96 this time will en age the next lower circularflange 92 on the integrator piston 89, so that the integrator piston ismoved further upward. inasmuch as the cam surface 100 of the integratorpiston 89 does not actuate lever 191 sutliciently to appreciably depressthe magnetic shunt 86 to a point where it will be held down by leakageflux from the coil 24, until toward the end of its upward movement, thissecond closely successive circuit-opening operation will, like thefirst, occur substantially instantaneously, with no delay due to dashpotac tion of cylinders 74, 77, and 78, and core 76. Springs 102 permit thelever 101 to be actuated in a clockwise direction by the cam surface 100while the shunting lever 86 is held in an upward position by the casing75. On the succeeding reclosing operation, the casing 75 and core 74will return freely to the position shown, so that this reclosingoperation will not be delayed. This second reclosing operation willresult in leaving piston 89 at the further advanced position describedabove, from which it eventually will reset in the. manner previouslydescribed if the breaker remains closed, so that an overload appearingon the circuit at a later time will result in the breaker operating inthe manner described above for the first and second closely succeedingcircuit-opening and closing operation. However, in the event theoverload continues after the second closely succeeding circuit-openingand closing operations, the breaker will again open, and this time theopening operation will be delayed, since the magnetic shunting lever 86is now depressed against the spacer 103 by lever 101. When the coil 24is energized, the shunting lever 86 is now held down by magnetic leakageflux from the coil, particularly across the groove 23, and preventsupward movement of the casing 75. The core 76 thereupon slowly movesupwardly in the casing against the dashpot action of the fluid thereinand the reset spring 81. When the core reaches some advanced position oftravel in which the air gap between it and the upper plate issufficiently reduced, the core and casing 75 will at first movetogether, the casing acting to force the magnetic shunt away from theupper plate 29 and against the collar 85 to effect separation of thebridging contact 36 from the stationary contacts 26. The opening of thecontacts is assisted by the spring 81, which is compressed and releasesits stored energy by expanding and assisting in forcing the casingupward relative to the core, so long as current fiows in the coil 24.

The circuit-closing operation of the breaker following the third openingwill not be delayed, since the casing 75 returns freely to its originalposition as shown, with the core in it. The core is quickly reset in thecasing, for the valve 83 acts to permit ready passage of fluid as thecore is forced downwardly in the casing by the spring 81. Inasmuch assuch third opening operation results in further advance of integratorpiston 89 to a position where it still actuates the lever 101 in aclockwise direction against the action of spring 102 for biasing themagnetic shunt into time-delaying position, the breaker may thencontinue to open and reclose if the overload continues, with eachopening being delayed by the dashpot action of core 76 in dashpot casing75, until finally pawl member 96 advances integrator piston 89 an amountsufiicient to cause the upper extension 9% thereof to engage extension129 of toggle lever 110, and move this lever upwardly overcenter so thattoggle spring 12 will maintain the contacts separated in the mannerpreviously described. It is thus apparent that toggle levers 110 and 114will be automatically moved upwardly overcenter to maintain the breakercontacts separated, only in response to a predetermined number ofclosely successive circuit-opening and closing operations, usually foursuch operations; however, in the event a lesser number of closelysuccessive opening and closing operations occur, the integratingmechanism will reset and the breaker contacts will be automatically heldopen only when the aforesaid predetermined number of opening and closingoperations occurs in close succession. Obviously, after the breakercontacts have been automatically actuated to a position where they areheld open by toggle spring 124, they can be reclosed only by manualoperation of toggle lever 114 in the manner previously described.

In the preferred sequence of operations leading to the breaker contactsbeing maintained in open circuit position mentioned above, that is, asequence of four operations, it will be apparent that with the apparatusdescribed above, the first two opening operations will occursubstantially instantaneously, and the second two opening operationswill be delayed with an inverse time-current characteristic due to thedashpot action of core 76 in dashpot casing 75. Moreover, the reclosingtimes in any such sequence of four closely successive opening andclosing operations will all be substantially instantaneous closingoperations, being delayed only slightly by the action of casing 75 as itmoves through the oil in the tank.

From the above description and the accompanying drawing, it will beapparent that we have provided a new and novel construction forautomatic reclosing circuit breakers. By using a sealed time-delaydashpot structure, different fluids may be used therein for obtainingdifferent time delays, regardless of the particular fluid used in thecircuit breaker tank. The accuracy of the time-delay device may beimproved as it may be manufactured as a separate integrated element. Byeliminating practically all dashpot action on the instantaneousopenings, the speeds of such openings can be increased. The sealed unitis impervious to dirt and the like, and can be used with reclosingbreakers of either the air or oil type.

Having described a preferred embodiment of the invention in accordancewith the patent statutes, it is desired that this invention be notlimited to this particular structure inasmuch as it will be apparent,particularly to persons skilled in the art that many modifications andchanges may be made in this particular structure without departing fromthe broad spirit and scope of the invention. Accordingly, it is desiredthat the invention be interpreted as broadly as possible and that it belimited only as required by the prior art.

' We claim'as our invention:

1. In a circuit interrupter, separable contacts, electroresponsive meansresponsive to an overload on a circuit to cause separation of saidcontacts, said means including a movable core and a dashpot membermovable relative to the core, means biasing said contacts to closefollowing a separation, and magnetic means responsive to energization ofthe electroresponsive means by said overload restricting movement ofsaid dashpot member to render the dashpot means effective to delayseparation of said contacts.

2. An automatic reclosing circuit breaker comprising separable contacts,electroresponsive means including a movable core operable in response toan overload on a circuit to eliect separation of said contacts,timedelay means having a part normally freely movable with the core topermit substantially instantaneous separation of said contacts andmovable relative to the core with delay, and means having a partactuated in response to said overload to engage and restrain said-partof the time-delay means to render the delay means effective to delaymovement of said core to effect separation of said contacts.

3. An automatic reclosing circuit breaker comprising, separablecontacts, means including a core movable in response to an overload on acircuit to efiect separation of said contacts, means operable toautomatically close said contacts, normally inetfective time-delay meansincluding a member movable relative to said core with delayed action andnormally movable freely with said core, and means including a magneticelement actuated during a circuit-opening and closing operation toengage and prevent movement of said member, said magnetic element beingactivated in response to an overload so as to render said time-delaymeans efiective only after reclosure of said contacts to delay the nextcircuit-opening operation.

4. In an automatic reclosing circuit breaker, separable contacts, meansincluding a movable core automatically responsive to overloads on acircuit for causing separation of said contacts, means responsive to acircuitinterrupting operation to automatically close said contacts,normally ineffective time-delay means normally movable with said core,and means including a normally ineffective cam and a lever operatedthereby actuated during a circuit-opening and closing operation and amagnetic member operable in response to an overload to prevent movementof said means movable with said core and render said time-delay meanseffective only after reclosure of the contacts to delay the next closelysucceeding circuit-opening operation, said last-mentioned means beingdisposed to reset to a normally ineffective position upon the lapse of apredetermined time after a circuit-opening and closing operation withouta subsequent circuit-opening operation.

5. An automatic reclosing circuit breaker comprising, separablecontacts, electroresponsive means including a core movable in responseto an overload to effect separation of said contacts, meansautomatically closing said contacts following a separation, time-delaymeans having a movable dashpot casing disposed about and biased relativeto said core, and means operable to restrict movement of said casing anddelay movement of said core in response to a particular number ofseparations of said contacts.

6. An automatic reclosing circuit breaker comprising, separablecontacts, electroresponsive means having a movable core member operablein response to an overload on a circuit to interrupt said circuit byseparating said contacts, means automatically closing said contactsafter a circuit-interrupting operation, time-delay means having amovable casing in which the core moves with a dashpot action and whichnormally moves with the core of said electroresponsive means, andmagnetic means having a releasable part operable by magnetic flux fromthe electroresponsive means to en age and to substantially limitmovement of said casing to utilize the dashpot action of the core in thecasing to delay separation of said contacts after a predetermined numberof operations of the electroresponsive means.

7. An automatic reclosing circuit breaker compising, separable contacts,electroresponsive means including a movable core responsive to anoverload on a circuit to effect separation of said contacts, meansbiasing said contacts to close following a separation, normallyineffective time-delay means having a movable element with amotion-delaying connection with the movable core, and magnetic meanshaving a part actuated by magnetic flux from the electroresponsive meansoperable during operation of said electroresponsive means to engage andrestrict movement of said element and render the delay means effectiveto delay movement of said core.

8. An automatic reclosing circuit breaker comprising, separablecontacts, electroresponsive means including a core of magnetic materialoperable in response to an overload current in a circuit to effectseparation of said contacts and interrupt said circuit, said contactsbeing biased to reclose following such a separation, time-delay meanshaving an element normally freely movable with said core, said elementbeing disposed in motion-retarding relation with said core for relativemotion of said core and element, and magnetic means operable in responseto energization of said electroresponsive means a predetermined numberof times to engage and impede movement of said element therebypermitting only delayed movement of said core.

9. An automatic reclosing circuit breaker comprising, separablecontacts, electroresponsive means responsive to an overload on a circuitto effect separation of said contacts, said electroresponsive meansincluding a movable magnetic core and said contacts being biased toreclose, time-delay means having a member disposed in delayed motionrelation with respect to the core and normally movable with said core,normally ineffective 10 magnetic means operable to an operating positionto engage and prevent movement of said member during an overload only,and means including a member actuated in response to a predeterminednumber of closely succeeding contact-separating operations to bias theaforesaid means to said position.

10. An automatic reclosing circuit breaker comprising, separablecontacts, means biasing said contacts together, electroresponsive meansincluding a movable core operable in response to an overload on acircuit to effect separation of said contacts to interrupt said circuit,normally ineffective time-delay means having a movable fluid containerin which said core is movably disposed, said container being normallymovable with the core in response to movement of said core for effectingseparation of said contacts, and magnetic means operable in response toleakage flux from said electroresponsive means to engage and preventmovement of the container so as to render the time-delay means effectiveonly until the core moves relative thereto in the container apredetermined amount.

11. An automatic reclosing circuit breaker comprising, separablecontacts, electroresponsive means having a movable core operable inresponse to an overload on a circuit to effect separation of saidcontacts to interrupt said circuit, time-delay means including anelongated longitudinally movable container in which said core is movablydisposed, said core providing a relatively snug fit in said containerand said container having therein a fluid which the core must displaceas it moves therethrough, means biasing the core relative to thecontainer, magnetic means operable in response to an overload to engageand prevent movement of the container until the core moves relativethereto a sufiicient distance to increase the force it exerts toovercome the effect of said magnetic means, biasing means normallyrendering the ma netic means ineffective, and means including countingmeans operable in response to a predetermined number of closelysucceeding circuit interruptions to actuate and render the magneticmeans effective when said number of closely succeeding circuitinterruptions have occurred.

12. An automatic reclosing circuit breaker comprising, separablecontacts, electroresponsive means including a core movable in responseto an overload to effect separation of said contacts, said contactsbeing biased to reclose following separation, time-delay means having acasing for said core normally movable with said core and movablerelative to the core with a dashpot action, and means operable inresponse to magnetic flux from the electroresponsive means to engage andprevent movement of said casing of said time delay means to delaymovement of said core.

13. An automatic circuit breaker comprising, separable contacts,electroresponsive means including a magnetic core movable in response toan overload to effect separation of said contacts, normally ineffectivetime delay means movable relative to the core with a delayed action,means operable to engage and limit movement of said time delay means,and counting means having a part advanced in response to a predeterminednumber of closely successive operations of said core for actuating saidlimiting means to make said limiting means effective and locking saidcontacts separated on different ones of said core operations.

14. An automatic reclosing circuit breaker comprising, separablecont-acts, electroresponsive means including a magnetic core movable inresponse to an overload to effect separation of said contacts, meansbiasing said contacts to reclose after separation, normally ineffectivetime delay means having a movable dashpot member movable with respect tosaid core with a dashpot action and normally biased relative to saidcore, normally ineffective magnetic means operable to engage andrestrain movement of said member to render said time delay meanseffective during an overload, and counting means having a part advancedin response to a predetermined number of circuit interruptions to effectoperation of the restraining means to render it effective.

15. An automatic reclosing circuit breaker comprising, separablecontacts, electroresponsive means including a magnetic core operable inresponse to an overload to effect separation of said contacts, meansreclosing said contacts following separation, movable dashpot meansnormally inefiective to delay movement of said core, normallyinoperative magnetic means operable to engage and restrain movement ofthe dashpot means during an overload only, and counting means operablein response to a predetermined number of closely successive contactseparating operations of said core to actuate and render the magneticmeans operable.

References Cited in the file of this patent UNITED STATES PATENTSSeifert Oct. 29, Corey June 25, Parsons Dec. 11, Wittingharn Ian. 31,Greene Mar. 14, Simon Feb. 10, Kane June 6, Lindstrom et al. Oct. 19,Madden Aug. 16, Sandin et al Aug. 15, Van Ryan et al. July 10, Van Ryanet al July 17, Hubbard 1 Sept. 18, Edwards Mar. 25,

Edwards Oct. 20,

